Q61 / 90 · JEE Main 2021 (27 Aug Shift 2) · Physics

For full scale deflection of total $50$ divisions, $50 mV$ voltage is required in galvanometer. The resistance of galvanometer if its current sensitivity is $2 div / mA$ will be:

Solution

$C . S . = \frac{θ}{I_{g}}$

$Ig = \frac{θ}{C . S .} = \frac{50 div}{2 div / mA} = 25 mA$

Potential difference $= 50 mV$

Resistance $= \frac{V}{I} = \frac{50 mV}{25 mA} = 2 Ω$

Hence, the correct answer is option: 'B'.